/Engine/Source/Editor/Sequencer/Public/MovieSceneTrackEditor.h
Initiate keying when there is more than one object to key (ie. drag and drop assets). This will allow for different behaviors, ie. keying all at the current time or keying one after the other.
static void BeginKeying ( [FFrameNumber](API\Runtime\Core\Misc\FFrameNumber) InFrameNumber )